mirror of https://github.com/ipxe/ipxe.git
462 lines
15 KiB
C
462 lines
15 KiB
C
#include "tftp.h"
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#include "tcp.h" /* for struct tcphdr */
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#include "errno.h"
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#include "etherboot.h"
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#include "tftpcore.h"
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/** @file
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*
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* TFTP core functions
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*
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* This file provides functions that are common to the TFTP (rfc1350),
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* TFTM (rfc2090) and MTFTP (PXE) protocols.
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*
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*/
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/**
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* Wait for a TFTP packet
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*
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* @v ptr Pointer to a struct tftp_state
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* @v tftp_state::server::sin_addr TFTP server IP address
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* @v tftp_state::client::sin_addr Client multicast IP address, or 0.0.0.0
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* @v tftp_state::client::sin_port Client UDP port
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* @v ip IP header
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* @v udp UDP header
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* @ret True This is our TFTP packet
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* @ret False This is not one of our TFTP packets
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*
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* Wait for a TFTP packet that is part of the current connection
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* (i.e. comes from the TFTP server, has the correct destination port,
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* and is addressed either to our IP address or to our multicast
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* listening address).
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*
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* Invoke await_tftp() using code such as
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*
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* @code
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*
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* if ( await_reply ( await_tftp, 0, &tftp_state, timeout ) ) {
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* ...
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* }
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*
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* @endcode
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*/
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int await_tftp ( int ival __unused, void *ptr, unsigned short ptype __unused,
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struct iphdr *ip, struct udphdr *udp,
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struct tcphdr *tcp __unused ) {
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struct tftp_state *state = ptr;
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/* Must have valid UDP (and, therefore, also IP) headers */
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if ( ! udp ) {
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return 0;
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}
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/* Packet must come from the TFTP server */
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if ( ip->src.s_addr != state->server.sin_addr.s_addr )
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return 0;
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/* Packet must be addressed to the correct UDP port */
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if ( ntohs ( udp->dest ) != state->client.sin_port )
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return 0;
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/* Packet must be addressed to us, or to our multicast
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* listening address (if we have one).
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*/
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if ( ! ( ( ip->dest.s_addr == arptable[ARP_CLIENT].ipaddr.s_addr ) ||
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( ( state->client.sin_addr.s_addr ) &&
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( ip->dest.s_addr == state->client.sin_addr.s_addr ) ) ) )
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return 0;
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return 1;
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}
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/**
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* Issue a TFTP open request (RRQ)
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*
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* @v state TFTP transfer state
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* @v tftp_state::server::sin_addr TFTP server IP address
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* @v tftp_state::server::sin_port TFTP server UDP port, or 0
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* @v tftp_state::client::sin_addr Client multicast IP address, or 0.0.0.0
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* @v tftp_state::client::sin_port Client UDP port, or 0
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* @v tftp_state::blksize Requested blksize, or 0
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* @v filename File name
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* @ret True Received a non-error response
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* @ret False Received error response / no response
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* @ret tftp_state::server::sin_port TFTP server UDP port
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* @ret tftp_state::client::sin_port Client UDP port
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* @ret tftp_state::blksize Always #TFTP_DEFAULT_BLKSIZE
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* @ret *reply The server's response, if any
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* @err #PXENV_STATUS_TFTP_OPEN_TIMEOUT TFTP open timed out
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* @err other As returned by udp_transmit()
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* @err other As set by tftp_set_errno()
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*
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* Send a TFTP/TFTM/MTFTP RRQ (read request) to a TFTP server, and
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* return the server's reply (which may be an OACK, DATA or ERROR
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* packet). The server's reply will not be acknowledged, or processed
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* in any way.
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*
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* If tftp_state::server::sin_port is 0, the standard TFTP server port
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* (#TFTP_PORT) will be used.
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*
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* If tftp_state::client::sin_addr is not 0.0.0.0, it will be used as
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* a multicast listening address for replies from the TFTP server.
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*
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* If tftp_state::client::sin_port is 0, the standard mechanism of
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* using a new, unique port number for each TFTP request will be used.
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*
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* For the various different types of TFTP server, you should treat
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* tftp_state::client as follows:
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*
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* - Standard TFTP server: set tftp_state::client::sin_addr to
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* 0.0.0.0 and tftp_state::client::sin_port to 0. tftp_open()
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* will set tftp_state::client::sin_port to the assigned local UDP
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* port.
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*
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* - TFTM server: set tftp_state::client::sin_addr to 0.0.0.0 and
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* tftp_state::client::sin_port to 0. tftp_open() will set
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* tftp_state::client::sin_port to the assigned local UDP port.
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* (Your call to tftp_process_opts() will then overwrite both
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* tftp_state::client::sin_addr and tftp_state::client::sin_port
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* with the values return in the OACK packet.)
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*
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* - MTFTP server: set tftp_state::client::sin_addr to the client
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* multicast address and tftp_state::client::sin_port to the
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* client multicast port (both of which must be previously known,
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* e.g. provided by a DHCP server). tftp_open() will not alter
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* these values.
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*
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* If tftp_state::blksize is 0, the maximum blocksize
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* (#TFTP_MAX_BLKSIZE) will be requested.
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*
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* On exit, tftp_state::blksize will always contain
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* #TFTP_DEFAULT_BLKSIZE, since this is the blocksize value that must
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* be assumed until the OACK packet is processed (by a subsequent call
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* to tftp_process_opts()).
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*
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* tftp_state::server::sin_port will be set to the UDP port from which
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* the server's response originated. This may or may not be the port
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* to which the open request was sent.
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*
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* The options "blksize", "tsize" and "multicast" will always be
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* appended to a TFTP open request. Servers that do not understand
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* any of these options should simply ignore them.
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*
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* tftp_open() will not automatically join or leave multicast groups;
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* the caller is responsible for calling join_group() and
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* leave_group() at appropriate times.
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*
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* If the response from the server is a TFTP ERROR packet, tftp_open()
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* will return False and #errno will be set accordingly.
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*/
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int tftp_open ( struct tftp_state *state, const char *filename,
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union tftp_any **reply ) {
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static unsigned short lport = 2000; /* local port */
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int fixed_lport;
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struct tftp_rrq rrq;
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unsigned int rrqlen;
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int retry;
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/* Flush receive queue */
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rx_qdrain();
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/* Default to blksize of TFTP_MAX_BLKSIZE if none specified */
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if ( ! state->blksize )
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state->blksize = TFTP_MAX_BLKSIZE;
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/* Use default TFTP server port if none specified */
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if ( ! state->server.sin_port )
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state->server.sin_port = TFTP_PORT;
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/* Determine whether or not to use lport */
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fixed_lport = state->server.sin_port;
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/* Set up RRQ */
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rrq.opcode = htons ( TFTP_RRQ );
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rrqlen = ( offsetof ( typeof ( rrq ), data ) +
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sprintf ( rrq.data,
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"%s%coctet%cblksize%c%d%ctsize%c0%cmulticast%c",
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filename, 0, 0, 0, state->blksize, 0, 0, 0, 0 )
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+ 1 );
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/* Set negotiated blksize to default value */
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state->blksize = TFTP_DEFAULT_BLKSIZE;
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/* Nullify received packet pointer */
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*reply = NULL;
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/* Transmit RRQ until we get a response */
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for ( retry = 0 ; retry < MAX_TFTP_RETRIES ; retry++ ) {
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long timeout = rfc2131_sleep_interval ( TIMEOUT, retry );
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/* Set client UDP port, if not already fixed */
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if ( ! fixed_lport )
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state->client.sin_port = ++lport;
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/* Send the RRQ */
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DBG ( "TFTPCORE: requesting %@:%d/%s from port %d\n",
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state->server.sin_addr.s_addr, state->server.sin_port,
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rrq.data, state->client.sin_port );
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if ( ! udp_transmit ( state->server.sin_addr.s_addr,
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state->client.sin_port,
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state->server.sin_port,
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rrqlen, &rrq ) )
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return 0;
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/* Wait for response */
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if ( await_reply ( await_tftp, 0, state, timeout ) ) {
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*reply = ( union tftp_any * ) &nic.packet[ETH_HLEN];
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state->server.sin_port =
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ntohs ( (*reply)->common.udp.dest );
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if ( ntohs ( (*reply)->common.opcode ) == TFTP_ERROR ){
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tftp_set_errno ( &(*reply)->error );
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return 0;
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}
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return 1;
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}
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}
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errno = PXENV_STATUS_TFTP_OPEN_TIMEOUT;
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return 0;
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}
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/**
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* Process a TFTP OACK packet
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*
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* @v state TFTP transfer state
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* @v oack The TFTP OACK packet
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* @ret True Options were processed successfully
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* @ret False Options were not processed successfully
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* @ret tftp_state::blksize Negotiated blksize
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* @ret tftp_state::tsize File size (if known), or 0
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* @ret tftp_state::client::sin_addr Client multicast IP address, or 0.0.0.0
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* @ret tftp_state::client::sin_port Client UDP port
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* @ret tftp_state::master Client is master
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* @err EINVAL An invalid option value was encountered
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*
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* Process the options returned by the TFTP server in an rfc2347 OACK
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* packet. The options "blksize" (rfc2348), "tsize" (rfc2349) and
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* "multicast" (rfc2090) are recognised and processed; any other
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* options are silently ignored.
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*
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* Where an option is not present in the OACK packet, the
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* corresponding field(s) in #state will be left unaltered.
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*
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* Calling tftp_process_opts() does not send an acknowledgement for
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* the OACK packet; this is the responsibility of the caller.
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*
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* @note If the "blksize" option is not present, tftp_state::blksize
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* will @b not be implicitly set to #TFTP_DEFAULT_BLKSIZE. However,
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* since tftp_open() always sets tftp_state::blksize to
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* #TFTP_DEFAULT_BLKSIZE before returning, you probably don't need to
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* worry about this.
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*/
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int tftp_process_opts ( struct tftp_state *state, struct tftp_oack *oack ) {
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const char *p;
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const char *end;
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/* End of options */
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end = ( ( char * ) &oack->udp ) + ntohs ( oack->udp.len );
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/* Only possible error */
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errno = EINVAL;
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for ( p = oack->data ; p < end ; ) {
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if ( strcasecmp ( "blksize", p ) == 0 ) {
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p += 8;
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state->blksize = strtoul ( p, &p, 10 );
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if ( *p ) {
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DBG ( "TFTPCORE: garbage \"%s\" "
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"after blksize\n", p );
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return 0;
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}
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p++;
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} else if ( strcasecmp ( "tsize", p ) == 0 ) {
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p += 6;
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state->tsize = strtoul ( p, &p, 10 );
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if ( *p ) {
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DBG ( "TFTPCORE: garbage \"%s\" "
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"after tsize\n", p );
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return 0;
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}
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p++;
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} else if ( strcasecmp ( "multicast", p ) == 0 ) {
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char *e = strchr ( p, ',' );
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if ( ( ! e ) || ( e >= end ) ) {
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DBG ( "TFTPCORE: malformed multicast field "
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"\"%s\"\n", p );
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return 0;
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}
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/* IP address may be missing, in which case we
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* should leave state->client.sin_addr
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* unaltered.
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*/
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if ( e != p ) {
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int rc;
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*e = '\0';
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rc = inet_aton ( p, &state->client.sin_addr );
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*e = ',';
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if ( ! rc ) {
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DBG ( "TFTPCORE: malformed multicast "
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"IP address \"%s\"\n", p );
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return 0;
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}
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}
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p = e + 1;
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/* UDP port may also be missing */
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if ( *p != ',' ) {
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state->client.sin_port = strtoul ( p, &p, 10 );
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if ( *p != ',' ) {
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DBG ( "TFTPCORE: garbage \"%s\" "
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"after multicast port\n", p );
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return 0;
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}
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} else {
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p++;
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}
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/* "Master Client" must always be present */
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state->master = strtoul ( p, &p, 10 );
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if ( *p ) {
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DBG ( "TFTPCORE: garbage \"%s\" "
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"after multicast mc\n", p );
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return 0;
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}
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p++;
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} else {
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p += strlen ( p ) + 1; /* skip option name */
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p += strlen ( p ) + 1; /* skip option value */
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}
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}
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if ( p > end ) {
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DBG ( "TFTPCORE: overran options in OACK\n" );
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return 0;
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}
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return 1;
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}
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/**
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* Acknowledge a TFTP packet
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*
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* @v state TFTP transfer state
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* @v tftp_state::server::sin_addr TFTP server IP address
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* @v tftp_state::server::sin_port TFTP server UDP port
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* @v tftp_state::client::sin_port Client UDP port
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* @v tftp_state::block Most recently received block number
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* @ret True Acknowledgement packet was sent
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* @ret False Acknowledgement packet was not sent
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* @err other As returned by udp_transmit()
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*
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* Send a TFTP ACK packet for the most recently received block.
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*
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* This sends only a single ACK packet; it does not wait for the
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* server's response.
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*/
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int tftp_ack_nowait ( struct tftp_state *state ) {
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struct tftp_ack ack;
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ack.opcode = htons ( TFTP_ACK );
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ack.block = htons ( state->block );
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return udp_transmit ( state->server.sin_addr.s_addr,
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state->client.sin_port, state->server.sin_port,
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sizeof ( ack ), &ack );
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}
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/**
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* Acknowledge a TFTP packet and wait for a response
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*
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* @v state TFTP transfer state
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* @v tftp_state::server::sin_addr TFTP server IP address
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* @v tftp_state::server::sin_port TFTP server UDP port
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* @v tftp_state::client::sin_port Client UDP port
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* @v tftp_state::block Most recently received block number
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* @ret True Received a non-error response
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* @ret False Received error response / no response
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* @ret *reply The server's response, if any
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* @err #PXENV_STATUS_TFTP_READ_TIMEOUT Timed out waiting for a response
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* @err other As returned by tftp_ack_nowait()
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* @err other As set by tftp_set_errno()
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*
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* Send a TFTP ACK packet for the most recently received data block,
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* and keep transmitting this ACK until we get a response from the
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* server (e.g. a new data block).
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*
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* If the response is a TFTP DATA packet, no processing is done.
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* Specifically, the block number is not checked to ensure that this
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* is indeed the next data block in the sequence, nor is
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* tftp_state::block updated with the new block number.
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*
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* If the response from the server is a TFTP ERROR packet, tftp_open()
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* will return False and #errno will be set accordingly.
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*/
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int tftp_ack ( struct tftp_state *state, union tftp_any **reply ) {
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int retry;
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*reply = NULL;
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for ( retry = 0 ; retry < MAX_TFTP_RETRIES ; retry++ ) {
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long timeout = rfc2131_sleep_interval ( TFTP_REXMT, retry );
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/* ACK the last data block */
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if ( ! tftp_ack_nowait ( state ) ) {
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DBG ( "TFTP: could not send ACK: %m\n" );
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return 0;
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}
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if ( await_reply ( await_tftp, 0, &state, timeout ) ) {
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/* We received a reply */
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*reply = ( union tftp_any * ) &nic.packet[ETH_HLEN];
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if ( ntohs ( (*reply)->common.opcode ) == TFTP_ERROR ){
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tftp_set_errno ( &(*reply)->error );
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return 0;
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}
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return 1;
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}
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}
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DBG ( "TFTP: ACK retries exceeded\n" );
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errno = PXENV_STATUS_TFTP_READ_TIMEOUT;
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return 0;
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}
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/**
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* Send a TFTP error
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*
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* @v state TFTP transfer state
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* @v tftp_state::server::sin_addr TFTP server IP address
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* @v tftp_state::server::sin_port TFTP server UDP port
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* @v tftp_state::client::sin_port Client UDP port
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* @v errcode TFTP error code
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* @v errmsg Descriptive error string
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* @ret True Error packet was sent
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* @ret False Error packet was not sent
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*
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* Send a TFTP ERROR packet back to the server to terminate the
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* transfer.
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*/
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int tftp_error ( struct tftp_state *state, int errcode, const char *errmsg ) {
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struct tftp_error error;
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DBG ( "TFTPCORE: aborting with error %d (%s)\n", errcode, errmsg );
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error.opcode = htons ( TFTP_ERROR );
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error.errcode = htons ( errcode );
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strncpy ( error.errmsg, errmsg, sizeof ( error.errmsg ) );
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return udp_transmit ( state->server.sin_addr.s_addr,
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state->client.sin_port, state->server.sin_port,
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sizeof ( error ), &error );
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}
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/**
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* Interpret a TFTP error
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*
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* @v error Pointer to a struct tftp_error
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*
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* Sets #errno based on the error code in a TFTP ERROR packet.
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*/
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void tftp_set_errno ( struct tftp_error *error ) {
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static int errmap[] = {
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[TFTP_ERR_FILE_NOT_FOUND] = PXENV_STATUS_TFTP_FILE_NOT_FOUND,
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[TFTP_ERR_ACCESS_DENIED] = PXENV_STATUS_TFTP_ACCESS_VIOLATION,
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[TFTP_ERR_ILLEGAL_OP] = PXENV_STATUS_TFTP_UNKNOWN_OPCODE,
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};
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unsigned int errcode = ntohs ( error->errcode );
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errno = 0;
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if ( errcode < ( sizeof(errmap) / sizeof(errmap[0]) ) )
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errno = errmap[errcode];
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if ( ! errno )
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errno = PXENV_STATUS_TFTP_ERROR_OPCODE;
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}
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